One possible big difference: Netgear with LPC enabled will enforce the DNS. So even if a smart child enters an alternate DNS for their device, the router will override their entered DNS and force use of the OpenDNS servers, still filtering the content.

However, on my tests with LPC OFF on my WNDR4500 with latest firmware (V1.0.1.40_1.0.68), if the local device specifies a different DNS the local DNS will prevail, bypassing the filtering. This is true even when I enter the OpenDNS servers as the designated DNS addresses for the router--they are not enforced.

I don't think it worked that way in the past. I believe the older firmware DID enforce the specified DNS, allowing me to use Home VIP as long as LPC was turned off.

Not sure if this holds true for WNDR4500, but many routers allow to specify outgoing firewall rules, so one can block port 53 pass-through or redirect port 53 (DNS) traffic to OpenDNS. This is enforcement of DNS then. I do this with my (non-Netgear) home router.